GOES-R IFR Probabilities (upper left), Suomi/NPP VIIRS Day/Night Band (upper right), Brightness temperature difference (10.7 micrometers – 3.9 micrometers) from GOES (lower left), Brightness temrperature difference (11.35 micrometers – 3.74 micrometers) from Suomi/NPP VIIRS (lower right), all around 0930 UTC on 31 August.

The presence of the Day/Night band on the VIIRS instrument on the Suomi/NPP satellite offers a unique method of validating the presence of fog or stratus at night.  During times near full moon (such as the Blue Moon on 31 August), the Day/Night band can detect low clouds using light reflected from the moon.  The GOES-R IFR probabilities show fog and low/stratus over southwestern Oregon;  a larger region of fog/low stratus stretched from just north of Crescent City, CA (where IFR conditions are reported) southward down the coast.  Note also a small patch over southwestern Washington and coastal northwest Washington (where IFR conditions are reported.  Cirrus clouds that prevent the detection of fog/low stratus from satellite are present stretching northeastward from the ocean off the central Oregon coast into central Washington.  There is a small signal in the GOES-R IFR Probability field underneath this upper cloud feature.

GOES-R IFR probabilties (Upper left), Suomi/NPP VIIRS day/night band (upper right), GOES-West Brightness Temperature Difference between 10.7 and 3.9 micrometer channels (Lower left), Observations (Lower right), all around 1200 UTC, 31 August

AT 1200 UTC, some benefits of the GOES-R IFR probability field are apparent.  The noisy signal over central and eastern Oregon is reduced, and a signal is present also underneath the thin cirrus streak that persists over extreme northwest Oregon.